Mouthguard



FIG. 1 is a front, left side perspective view of a mouthguard showing my new design;

FIG. 2 is a front view thereof;

FIG. 3 is a back view thereof;

FIG. 4 is a left side view thereof;

FIG. 5 is a right side view thereof;

FIG. 6 is a top view thereof;

FIG. 7 is a bottom view thereof; and,

FIG. 8 is a rear perspective view thereof.

Features shown in dashed lines form no part of the claimed design. 

CLAIM The ornamental design for a mouthguard, as shown and described. 